The United States has attacked a Syrian air base with 50-60 cruise missiles in response to a chemical weapons attack it blames on President Bashar Assad.
North Korea is continuing to talk tough with the US, this time promising their "grim action" is going to bring "catastrophic consequences" to the world.
Officials in Pyongyang have provided a statement to CNN where they justify their "self-defensive and pre-emptive strike capabilities with the nuclear force at the core" on the build up of US naval forces near the Korean Peninsula, according to news.com.au.
American forces announced yesterday that the USS Carl Vinson, loaded with fighter jets, had been pulled from its planned military exercises in Australia and ordered towards the Korean Peninsula.
Three guided-missile destroyers and cruisers joined the armada, which left from Singapore on Saturday.
Pyongyang has described the situation as "grim", according to the CNN statement.
"We will make the US fully accountable for the catastrophic consequences that may be brought about by its high-handed and outrageous acts," it read.
According to military and intelligence sources who spoke to The New York Times, the US's show of force was timed around the most important day on the North Korean calendar, the anniversary of the birth of Kim Il-sung, who founded the nation and is the late grandfather of current leader Kim Jong-un.
In its response to America's naval movements today, the regime's foreign ministry said the US's "reckless moves for invading the DPRK have reached a serious phase," and issued the warning that it was ready for war, AFP reported.
"The DPRK is ready to react to any mode of war desired by the US," North Korea's state-run news agency said.
There is speculation that Pyongyang will mark the occasion with by testing missiles or possibly a nuclear device.
The rogue state has a history of launching missiles and taking provocative actions on the anniversary, and satellite imagery suggests Kim Jong-un might take the opportunity to flex his military muscles on April 15.
South Korea's top nuclear envoy Kim Hong-Kyun has backed up the theory, warning that the North may stage a "strategic provocation" to mark the date.
The US has notified Australia that it is prepared to shoot down any missiles launched on Saturday and the Pine Gap military intelligence base in central Australia is on standby, The Daily Telegraph reports.
Donald Trump is yet to discuss publicly his decision to move the warships to waters off North Korea. Photo/AP
Trump is emboldened after his widely endorsed air strike against a Syria last week, where he ordered 59 Tomahawk missiles to bomb an air base in response to a chemical weapons attack in the country that killed more than 80 civilians, including children.
However, the US strike against Syria was unlikely to deter Kim Jong-un from developing his nuclear weapons program, former Pentagon official Daniel Goure told US news channel CNBC.
"If you are the North Korean leader, you say, 'Wow, I could be next'," said Goure, who is now a spokesman for defence think tank the Lexington Institute.
"For them, I think the answer is straight forward - you can't trust the Americans."
He said the situation on the Korean Peninsula was "hugely near the tipping point".
"It's quite possible it could be a very intense, bloody war," he said.
Meanwhile, another expert has warned that any US strike against the isolated nation could trigger a much larger military conflict that draws in China or Japan.
"The upside is that the United States may be able to denuclearise the North by force ... but it will come at a huge cost to the region and to the United States," Asan Institute for Policy Studies analyst James Kim told AFP.
North Korea has not addressed the US's provocative move in the western Pacific, but it has denounced the attack on Syria as an act of "intolerable aggression".
Meanwhile, China and South Korea have agreed that there should be "strong" new measures to punish the North if it pushes ahead with nuclear weapons testing.
Trump is also yet to make any public comments about the movement of the US warships, but his Syrian missile strike is being interpreted as a warning to North Korea.
The President's chief national security adviser, HR McMaster, said the Korean strategy was aimed to give the President a "full range of options to remove that threat to the American people and to our allies and partners in the region".
General McMaster said North Korea was "a rogue regime that is now a nuclear capable regime".
"What must happen is the denuclearisation of the Korean Peninsula," General McMaster told Fox News Sunday.
"North Korea has been engaged in a pattern of provocative behaviour."
US Pacific Command spokesman Dave Benham told AFP the diversion of the warships was a "prudent" move due to North Korea's "reckless, irresponsible and destabilising program of missile tests and pursuit of a nuclear weapons capability".
